The objective of the proposed research is to extend our information regarding hexose metabolism during aging in Dictyostelium discoideum. Evidence for a uronic acid pathway will be investigated, in order to expose unique characteristics of the metabolic network under analysis and to test specific predictions regarding the effects of perturbing this system with exogenous glucose. Those enzymes directly involved in uronic acid metabolism will be fractionated, to determine the reaction mechanism and relevant kinetic parameters. Flux studies utilizing labelled glucose and galactose will be undertaken to evaluate the contributions of the uronic acid pathway to hexose metabolism. The uronic acid pathway will be incorporated into the present kinetic model for carbohydrate metabolism in this organism.